Fix generating standalone script in bundle context
Fix generating standalone script in bundle context

`bundle exec rake standalone` in development mode would try to shell out
to `ruby --disable-gems` to detect 1.9 support, but that would fail
because Bundler tries to propagate itself through RUBYOPT and
`--disable-gems` obviously doesn't play along with it.

whilp/hub,nmfzone/hub,aereal/hub,nlutsenko/hub,haikyuu/hub,nmfzone/hub,nlutsenko/hub,hopil/hub,cpick/hub,jpkrohling/hub,elancom/hub,tomasv/hub,naru0504/hub,pcorpet/hub,sbp/hub,elancom/hub,rlugojr/hub,ryo33/hub,naru0504/hub,github/hub,ASidlinskiy/hub,aspiers/hub,nlutsenko/hub,codydaig/hub,xantage/hub,naru0504/hub,RichardLitt/hub,rlugojr/hub,adjohnson916/hub,AndBicScadMedia/hub,sbp/hub,ASidlinskiy/hub,hb9kns/hub,hb9kns/hub,RichardLitt/hub,dongjoon-hyun/hub,SanCoder-Q/hub,pankona/hub,ZenPayroll/hub,hopil/hub,jingweno/hub,isundaylee/hub,xantage/hub,dongjoon-hyun/hub,aereal/hub,github/hub,isundaylee/hub,dev4mobile/hub,ASidlinskiy/hub,terry2000/hub,ryo33/hub,pwaller/hub,haikyuu/hub,hb9kns/hub,nmfzone/hub,pankona/hub,jpkrohling/hub,dongjoon-hyun/hub,pwaller/hub,RichardLitt/hub,Gusto/hub,elancom/hub,boris-rea/hub,pcorpet/hub,boris-rea/hub,pankona/hub,cpick/hub,AndBicScadMedia/hub,jingweno/hub,dev4mobile/hub,sideci-sample/sideci-sample-hub,isundaylee/hub,ZenPayroll/hub,dev4mobile/hub,jingweno/hub,tomasv/hub,xantage/hub,hopil/hub,SanCoder-Q/hub,Gusto/hub,aereal/hub,pcorpet/hub,aspiers/hub,github/hub,tomasv/hub,pwaller/hub,whilp/hub,whilp/hub,adjohnson916/hub,jpkrohling/hub,AndBicScadMedia/hub,codydaig/hub,sbp/hub,terry2000/hub,adjohnson916/hub,codydaig/hub,SanCoder-Q/hub,haikyuu/hub,ryo33/hub,rlugojr/hub,boris-rea/hub,cpick/hub,sideci-sample/sideci-sample-hub,terry2000/hub,github/hub,aspiers/hub